Should I maintain same asset allocation in each investment vehicle?

[ardrum]

I am going with an 80/20 domestic/international equity mix for my overall investing allocation (I'm 100% equities and plan to continue that indefinitely).  I have a 401k, tIRA, Roth IRA, HSA, and taxable account.  As of now I have been aiming for this same 80/20 ratio in each, though I just started my taxable account and currently just hold VTSAX after raising the $3k minimum buy-in.  I'm wondering if there would be good reason to a) just stick to VTSAX fund in the taxable account (perhaps related to some sort of tax efficiency?) and otherwise mildly increase the international holdings in other accounts to maintain the overall 80/20 ratio, or b) save up the $3k to get VTIAX as well in the taxable category and otherwise just make additional contributions to pursue that 80/20 target there as well.  Perhaps it doesn't really matter much (other than the time it would take to raise the $3k minimum for VTIAX), but I value hearing opinions.

[Car Jack]

Maintaining an AA in each account is needlessly complex, can be overly expensive and makes rebalancing a pain.  From a tax perspective, bonds don't work in taxable.  As an example, I have 9 accounts in total.  My IRA holds the funds I rebalance.  The rest hold one fund each.  For me to rebalance, I can do it in about 2 minutes and be done.  All of my taxable are equivalent to VTSAX.

[Telecaster]

I am going with an 80/20 domestic/international equity mix for my overall investing allocation (I'm 100% equities and plan to continue that indefinitely).  I have a 401k, tIRA, Roth IRA, HSA, and taxable account.  As of now I have been aiming for this same 80/20 ratio in each, though I just started my taxable account and currently just hold VTSAX after raising the $3k minimum buy-in.  I'm wondering if there would be good reason to a) just stick to VTSAX fund in the taxable account (perhaps related to some sort of tax efficiency?) and otherwise mildly increase the international holdings in other accounts to maintain the overall 80/20 ratio, or b) save up the $3k to get VTIAX as well in the taxable category and otherwise just make additional contributions to pursue that 80/20 target there as well.  Perhaps it doesn't really matter much (other than the time it would take to raise the $3k minimum for VTIAX), but I value hearing opinions.

If you are going to hold VTIAX, keep it in the taxable account because you will get a credit for foreign tax paid.  For that reason, you probably don't want to have VTIAX in any of your retirement accounts:

https://www.irs.gov/individuals/international-taxpayers/foreign-tax-credit

Another thing to keep in mind is that your 80/20 allocation is a bit arbitrary to start with (why not 78/22?)  so it is no great tragedy if you out of balance for while.   In fact, some studies show the optimal rebalance period is measured in years.   So, IMO, it isn't something to overly concern yourself with. 

[MustacheAndaHalf]

Actually 80/20 has the highest probability of providing an international diversification benefit.  Those willing to take more risk (of not benefiting from international) can allocate from 20-40%, according to a white paper by Vanguard "Global Equity Investing":
https://www.vanguard.com/pdf/ISGGEB.pdf

Total International issues 3% in dividends, while U.S. Total Stock Market puts out 2% in dividends.  So there's more dividends to pay taxes on, and they are taxed more (U.S. total stock market dividends are ~95% qualified, versus 80-85% for total international).  So at current dividend rates, international and U.S. aren't that different in taxable.

[ardrum]

Thanks for the input everyone!